Power system



@my 'l 1943. M, A. EDWARDS Y 232452935 POWER SYSTEM F3166. March 26, 1942 gine within a given range of load current and voltage variations below a predetermined electric current.

The generator voltage-current characteristic for this condition of operation isrepresented by the curve b-c in Fig. 3 for a given throttle setting, and the diierence between the curve b-c and the curve a represents the losses of the system, that is, the difference between the engine output and the main generator output. It is to be noted that .the power output from b to c plus the losses of the electricalgenerating equipment, machines and exciting system, equal the substantially constant output power of the engine as shown by curve a.' At the higher current values the electrical losses'are higher and the curve b-c varies more from the curve a. The generator characteristic curve h-df-e-f is for another engine throttle setting. i

In order to limitthe maximum current of the main generator, a eld exciting winding 21 is arranged on the secondary commutating axis of the amplidvne generator and is adapted to pro.- vide a component of excitation thereto in opposition to the component of excitation provided by the eld exciting winding 22 when the main generator load current exceeds a predetermined value to reduce the excitation of the amplidyne exciter under this condition. This -is obtained by connectirm this iield exciting winding across a potentiometer arrangement such that the eldexciting winding remains de energized below. a predetermined load current. above lwhich the energization ofthe winding is dependent upon the value of the main generator load current. One terminal of the eld exciting winding 21 is connected to one side 28 of the main generatorcommutating field exciting winding I4, and

theother terminal thereof is connected to a central point 29 between a pair ot rectiers 33 and 3|, which may be of the lcopper oxide type. The other side of the rectier 30 is connected to a terminal 32 of a potentiometer resistance 33, s and the otherside of the rectifier 3i is connected to the other terminal 34 of the potentiometer resistance 33. The central pointV 35 of the poamount, the eld exciting winding 21. tends to decrease the excitation of the amplidyne exciter I5 which decreases the excitation of the main generator eld exciting winding I3, causing the main generator to drop some of its load. In this manner, the 'leld exciting winding 21 of the amplidyne exciter will automatically and inherently limit the maximum load current on the main generator. 'I'his operation is represented by curves c-f and e.-f in Fig. 3. .l

In order to limit the maximum current of the main generator iild exciting winding I3 to a safe operating value, a iield exciting winding 38- is arranged on the secondary commutating axis of the amplidyne generator I 5 and is adapted to provide a component of excitation thereto in opposition to the component o! excitation provided by the control eld exciting winding 22 when the current of the field exciting winding I3 of the main generator exceeds a predetermined value. 'I'his is obtained by connecting this eld exciting vwinding across a potentiometer arrangement such'that the held-exciting winding 38 remainsdeenergized below a predetermined main generator field current, above which the energization of the `winding is dependent upon the value of the currentthrough the ileld exciting winding I3, One terminal of the field exciting winding 38 is connected to one side 33 of the resistance I1 in series with the field exciting winding I3, and the other terminal is connected to a centralpoint 40 between a pair of rectiiiers 4i and 42, which may be of the copper oxide type. The other s ide of the rectifier 4I is connected to a terminal 43 of a potentiometer resistance 84, and the other side of the rectier 42 is connected .to the other terminal '4.5 of the potentiometer resistance 44. The central point d3 oi' the potentiometer resistance 44 is conoi electrical power supply, such as-the battery 23, in series with a resistance 48. The rectiers 4I and 42 are connected across the resistance 44 tentiometer resistance 33 is connected to the other terminal 3S of the main generator commutating field exciting winding I4. The terminals 32 and 36 of the potentiometer resistance -33 are connected across a source of electrical power supply, such as the battery 23, in series with a resistance 31. The rectiers B; and 3i are connected across the resistance andthe battery 23 in such a manner as to prevent a short circuit across the resistor and the battery.

'I'he commutating iield'exciting winding i3 isv connected across one branch of the resistor 33 between the terminals 34 and 35, such that as long as the drop across the commutating iield exciting winding I4. remains higher than the drop across this branch-of the resistor 33, current .will not ow through the field excitingv winding 21.v However, when the drop across the field exciting winding vI4 exceeds the drop across the resistor 33'between. the terminals 34 and 35., current will pass-through the field exciting winding 21, thereby energizing the same in proportion to the drop across the commutating field exciting winding whichis proportional to and dependent on the load current of the main generator II. The rectiiier 30 prevents the ow'of current through the neld exciting winding 21 in the opposite direction. Thus, when the load on the main generator exceeds .a predetermined and the battery 23 in such a manner as to prevent a short circuit across the resistor and the battery. The resistance I1 is connected across one branch of the resistor 44 between the terminals 45 and 46, such that as long as the drop across the resistance I1, thatis, the current in the neld exciting winding I3, remains higher.

A than the drop across this branch of the resistor 45, current will not .now through the rleld excitciting winding 33, which is dependent onthe enr ergization of winding I3, tends to decrease the excitation oi' the amplidyne exciter I5 which decreases the excitation ofthe main generator eld exciting winding I3. In this manner, thev field excitingv winding 38 of the amplidyne exciter will automatically limit the maximum en ergization current in the field exciting winding i3 substantially to a predetermined maximum value. This produces themain generator chairingwinding 38. However, when the drop across acteristic curve represented in Fig. 3 by curves y-b and hf-d.

In order to stablize the operation of the excitation system, a eld exciting winding I9 is connected in series with a condenser 5 0 across the secondary terminals of the amplidyne exciter i5. This field exciting winding normally is not energized, but if the amplidyne exciter tends to become unstable, the field exciting winding 49 will be energized bythe variations in the voltage thereacross, and it is arranged on the machine to provide a component of excitation thereto which winding Il from the battery by varying the battery voltage drop between a terminal 'il and the control member 1l on a potentiometer resistance 12 connected across the battery t5. Under normal operating conditions, the amplidyne exciter control field exciting winding 8E is connectedacross the battery potentiometer 'i2 in series with the pilot generator I8 opposed to the battery voltage through a rectifier i3, such as copper oxide rectifier, to prevent reversal of l current through this circuit if the pilot generator tends to generate voltage therein in opposition.-

.to the voltage change causing the energization of the field exciting winding 49, thereby tending to damp out such transient variations and to stabilize the machine. The relative direction of the various components of excitation is indicated by arrows on the respective field exciting windings. -4

In Fig. 2 is shown another embodiment of my invention wherein an engine Bi is :arranged to drive a main generator provided with an armature B2 connected to supply power to series traction driving motors 5I, As in Fig. l, the characteristics of the `main .generator are controlled ;by a main neld exciting winding 5I, and a commutating field exciting winding 55 is connected in series with the main load circuit of the main generator. The held exciting winding il is adapted to' be energized by an armature reaction excited dynamo-'electric machine or amplidyne exciter 5l, the secondary vor load brushes B1 and il of which are connected in series with the field exciting winding Il, an exciter compensating winding il, and a resistance el in opposition to the voltage of the -main generator 52. A primary circuit is completed through the amplidyne exciter armature N by short-circuiting primary brushes Bi and 02 of the machine by'an external conductor I3.

In order to obtain the desired substantially constant power engine output or generator input characteristic, that is, generator power output together with the losses ofthe electrical system and machines as represented by the engine output curve a in Fig. 3, the main generator characteristic'is regulated by controlling the energization of the main field exciting winding Il through the control of the amplidyneexciter. A control neld' lexciting winding Il is arranged to provide the controlling excitation to the amplidyne exciter and is energized by a suitable source of electrical power supply including a battery Il in series with and in opposition to a speed responsive source oi' electrical potential provided by a substantially unsaturated pilot generator 6B. This pilot generator is arranged to provide an electric voltagesubstantially responsive to the speed of the engine 5i by being driven at a speed proportional to the engine speed. Since the voltage of the battery 65 may vary with its charge and its internal voltage drop, the pilot generator is excited by a field exciting winding i1 connectA ed through a resistanee Il across the battery Il.

This assures. a substantially constant voltage relationship between the battery l5 and the generator il irrespective of the battery voltage.

' Different patterns of characteristics may be obtained by varying the throttle position of the engine il, The excitation of the main generator t! is controlled directly by connecting a throttle control lever il to .a battery voltage bias control member 18 which controls the voltage impressed on the amplidyne exciter field exciting voltage should tend to drop below the battery voltage, and through two relays having contacts N and 1I closed by contactors 1l and 11, respectively. Variations in engine speed tendl to produce corresponding variations in the pilot exciter voltage and, thereforefin the energizations of the exciter field exciting winding il. This is reiiected bythe amplidyne exciter in corresponding variations in the energization of the main generator neld exciting winding 5l, thereby tending to increase the load on the main generator 52 if its speed increases and to decrease the load thereon if its speed decreases. Should the speed oi' the main generator fall below a predetermined cient to prevent overspeeding of the engine, particularly since the battery voltage would be suddenly increased-*before the pilot generator voltage would have time to build up, with the result that the field exciting winding 6l, and consequently the main field exciting winding generator I4, would be substantially deenergized, there- 4by removing all load from the main generator and the engine. In order to prevent this undesirable condition, a field exciting winding 1I is arranged on the amplidyne exciter andconnectved through a condenserv 19 directly across the pilot exciter l.. Thus, when there is a sudden change in the voltage of the pilot exciter, this field exciting winding 1l is energized rapidly to provide a rapid change in a corresponding sense in the excitation of the amplidyne exciter,

; thereby providing for the rapid increase or def crease in the energization of the main generator field exciting winding lil and a corresponding rapid change in the load on the main generator to prevent unloading or overloading of the' encosine l'ns It is desirable that transient variations in the amplidyne exciter circuit should not aifect its operation, and a field exciting winding "is arranged on the amplldyne exciter secondary commutating axis connected directly across its secondary circuit through a condenser Il and a shunting resistance l2 to provide a component oi excitation along the secondary commutating axis of the machine in opposition to the control component of excitation provided by the field exciting winding 8|. This field exciting winding IU is slightly energized at all times through the resistance 82 and transient variations cause the condenser 1I to provide an energization to the field exciting winding '18, tending to oppose such ergization current.

changes and'to stabilize the operation of the machine.

In order to prevent damage to the system', it is desirable that the maximum load current on the main generator" should be limited to a predetermined maximum value. This .protection is provided by arranging the contacter i6 to operate in response'to a predetermined voltage drop across the commutating iield exciting winding 55'of the main generator as this drop is proportional to the main load current. The contactor 'I6 is arranged to be operated by a relay coil 83 connected in series with a transformer winding 8l across the maingenerator commutating ileld exciting winding 55 and in series with a variable control resistance 85. The transformer is provided with a secondary winding 8B connected across the secondary brushes l and 58 of the amplidyne exciter 56, such that the relay contactor 16 will vibrate whenever 'the load current reachespa predetermined maximum value. This causes thecontactor 'I6 to deenergize the amplidyne exciter control eld excitingwindlng il.

periodically and causes the main generator to drop its load. Thus, this relay will vibrate to limltthe load on the main generator, so as to limit automatically and inherently the maximum `loadA current and power output of the main generator and will provide a characteristic thereto which is represented in Fig. 3 bythe curves c--f and e-f. l

In order to prevent overheating of the main generator eld exciting winding by excessive current, the contactor 11 is arranged to be operated by relay coll B1 connected in series with a transformer winding 88 across the resistance 80 which is in series with the generator iield exciting ywinding 5l.l Thus, the voltage across the transformer winding 8B `and the relay coil 81 is directly proportional to the current in the neld exciting, winding. The transformer is proaseaaec pended. claims to cover all modifications Vwhichdo not depart from the-spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An excitation system for a dynamo-electric machine in a power system including a eld exciting winding, dynamo-electric means arranged to energize said field exciting winding, and means for varying thevenergization provided by said dynamo-electric means to regulate the power output of the dynamo-electric machine to a value such that said power output together with the losses of said power system and said machine is a substantially constant value withina given range of current and voltage variations below a predetermined electric current, said dynamoelectric ,means including means for varying theenergization of said dynamo-electric machine eld exciting winding for limiting the electric current of said dynamo-electric machine to a predetermined maximum value.

2. An excitation system for a dynamo-electric vmachine in a power system including a iield exciting winding, dynamo-electric means arranged to energize said iield exciting-winding, and means for varying the energization provided by said dynamo-electric means to regulate 'the power output of the dynamo-electric machine to a value such that said power output together with the losses of said power system and said machine is a suizostantiallyr constant value Within a given vided with a secondary winding connected across the secondary of the amplidyne exciter such that if the current in the iield. exciting winding 54 exceeds 4a predetermined value, the relay coil B7 will open the contactor 'il to deenergize the main generator field exciting winding 54 and automatically limit its maximum en- This, however, causes the relayV coil 81 to be deenergized, thereby reclosing the contactor il on the contacts '35. This operation is'indicated in Fig. 3 by curves g-b andv h-d. Since the inductances oi a,v system are such that the relay coils 83 and @i may not respond as rapidly as desired if merely connected 'across the controlling voltages, the transformer connections described above are provided to assure a more rapid response, and these transformers are connected directly 'across the amplidyne exciter and are immediately responsive to the variations produced bythe operation of the relays. Y

In order to start the main generator, it is provided with a field exciting winding e@ connected in series with a starting switch 9i, and is adapted to be connected across the battery G5 in series with the main generator armature 52 by closing the switch 9|. Under normal operating condirange of current and voltage variations below a predetermined electric current, said dynamoelectric means including means for varying the energization/ of vsaid dynamo-electric machine ileld exciting. winding for limiting the electric current of said dynamo-electric machine to a predetermined maximum value, said means being arranged to limit the energizatlon of said field exciting winding substantially to a predetermined maximum value. y

3. An excitation system for a dynamo-electri machine in a power system including a field exciting winding, dynamo-electric means arranged to energize said field exciting winding, and means for varying automatically the energization provided by said dynamo-electric machine to regulate the power output of the dynamo-electric machine l to a value such that said power output together `with the losses of said power systemand said machine is a substantially constant value within a given range of current and voltage variations below a predetermined electric current, said dynamc-electric means including means for varying the energization of said dynamo-electric ma'- chine leld exciting` winding for limiting automatically the electric current of said dynamoelectric machine to a predetermined maximum value, said means being arranged to limit auternatlcally the energization of said eld exciting winding substantially to a predetermined maximum value. v

d. A power system including a prime mover, a main electric generator driven by said prime mover, an excitation system for said main generator including a iield exciting winding, dynamoelectric means arranged to energize said field exciting winding, and means for varying the energization provided by said dynamo-electric ations below a predetermined value of electric current, said dynamo-electric means including means for varying the energizatlon of said generator field exciting winding for limiting the electric current of said main generator substantially to a predetermined maximum value, said last-mentioned means being adaptedto limit the energization of said main generator field exciting winding substantially to a predetermined maximum value.

5. An excitation system for a ,dynamo-electric machine of a power system including a field exciting winding, an auxiliary dynamo-electric ma-l chine arranged to energize said field exciting winding, means including a second field exciting winding for varying the energization provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said firstmentioned dynamo-electric machine to avalue such that said output together with the losses of said power system and said machine is a substantially constant value within a given range of current and voltage variations below a predetermined value of electric current, means for varying the energization provided by said auxiliary dynamo-electric machine to vary 'inherently the current of said first-mentioned dynamo-electric machine when the electric current thereof tends to exceed said predetermined value, and means for limiting the energization of said first-'mentioned eld exciting winding substantially to a predetermined maximum value.

6. An excitation system for a dynamo-electric machine of a power system including a field exciting winding, an auxiliary dynamo-electric machine arranged to energize said field exciting winding, means responsive to the speed of said first-mentioned dynamo-electric machine for varying the energization provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said first-mentioned dynamo-electric machine to a value such that said output together with the losses of said power system and said machine is a substantially constant valuewithin a given range of current and voltage variations below a predetermined value of electric current, means'ior-Varying the energization provided by said auxiliary dynamo-electric machine to vary inherently the current of said first-mentioned dynamo-electric machine when the electric current thereof tends to exceed'said predetermined value, and means for limiting the energization of said first-mentioned field exciting winding substantially to a predeterl mined value.

7. An excitation system for a dynamo-electric machine of a. power system including a field exciting winding, an auxiliary dynamo-electric machine arranged to energize said field exciting winding, means including a second field exciting winding arranged to be energized substantially responsive to the power of said power system for varying the energization provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said firstmentioned dynamo-electric machine to a value such that said power output together with the losses of said power system and said machine is .a substantially constant value within a' given range of current and voltage variations below a.

predetermined value of electric current, means for varying the energizatlon provided by said auxiliary dynamo-electric machine to vary inherently the current of said first-mentioned dyname-electric machine when the electric current .thereof tends to exceed said predetermined value,

and means for inherently limiting the energization provided by said auxiliary dynamo-electric machine to said first-mentioned field exciting winding substantially to a predetermined maximum value.

8. An excitation system for a dynamo-electric machine of a power system including a field exciting winding, an auxiliary dynamo-electric machine arranged to energize'said field exciting winding, means including a second field exciting winding for said auxiliary dynamo-electric machine for varying the energization provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said firstmentioned dynamo-electric machine to a value such that; said output together with the losses of said power system and said machine is a substantially constant value within a given range of current and voltage variations below a predetermined value of electric current, means for varying the energization provided by said auxiliary dynamo-electric machine to vary inherently the current of said first-mentioned dynamoelectric machine when the electric current thereof tends to exceed said predetermined value, and means for limiting the energizatlon of said first-mentioned field exciting winding substantially to a predetermined maximum value.

9. An excitation system for a dynamo-electric machine of a power system including a field exciting winding, an auxiliary dynamo-electric machine arranged to energize said field exciting winding, means including a second field exciting winding for varying the energizatlon provided by said auxiliary dynamo-electric machine to regulate automatically 'the power output of said first-mentioned dynamo-electric machine to a value such that said output together with the losses of said power system and said machine is a. substantially constant value with- 1n a given range of current and voltage variations below a predetermined value of electric current, and means including a third field exciting wincling for varying the energization provided by said auxiliary dynamo-electric machine to vary automatically the current of said firstmentioned dynamo-electric machine when the electric current thereof tends to exceed said predetermined value.

10. An excitation system for a dynamo-electric machine of a power system including a field exciting winding, an auxiliary dynamo-electric machine arranged to energize said field exciting winding, meansincluding a second field exciting winding for varying the energization provided by said auxiliary dynamo-electric machine to regulate automatically the power output of said first-mentioned dynamo-electric machine to a value such that said output together with the losses of said power system and said machine is av substantially constant value within a given range of current and voltage variations below a predeterminedl value of electric current, and means including a third field exciting winding for varrying the energization provided by said auxiliary dynamo-electric machine to vary automatically the current of said first-mentioned dynamo-electric machine when the electric current thereof tends to exceed said predetermined value, said last-mentioned means also being adapted to limit automatically the energizatlon of said first-mentioned field exciting winding substantially to a predetermined maximum value.

11. An excitation system for a dynamo-electric machine of a power system including a field exciting winding, an auxiliary dynamo-electric machine arranged to energize said ileld exciting winding, means including .a second eld exciting winding for varying the energization provided being adapted to limit'the energization o! said inst-mentioned field exciting' winding `substantially to a predetermined maximum value.

12. An excitation system for a dynamo-electric A machine of a power system including a eld exciting winding, an auxiliary dynamo-electric machine arranged to energize said iield exciting winding, means including a second iield exciting winding for said auxiliary dynamo-electric machine for varying the energization provided` by said auxiliary dynamo-electric machine to regulate inherently the power output o! said mst-mentioned dynamo-electric machine to a value such that said output vtogether with the losses of said power system and said machine is a substantially constant value within a givenrange of current and voltage variations below a predetermined value of electric current, a third iield excitingv winding for said auxiliary dynamoelectric machine, and means for varying the energization provided by said auxiliary dynamo-` electric machine to limit the current of said rstmentioned dynamo-electric machine to a predetermined maximum value.

when the electric current thereof tends to exceed said predetermined. value, said last-mentioned means also being adapted to limit'the ,energization of said first-mentioned field exciting winding substantially to a predetermined maximum value.

15. An excitation system'for a dynamo-electric machine of a, power system including a eld exciting winding, an auxiliary dynamo-electric machine arrangedl to energize said field exciting winding, means including a second eld exciting winding for said auxiliary dynamo-electric machine for varying the energization provided by said auxiliary dynamo-electric machinev to regulate automatically the power output of said nrstmentioned dynamo-electric machine to a value such that said output together with the losses of said power system and said machine is a substantially constant value within a given range o! current and voltage variations below a predetermined value of electric current, and means including a third iield exciting winding for varying the energization provided by said auxiliary dynamo-electric machine to vary automatically the current of said mst-mentioned dynamo-elec tric machine when the electric current thereof tends toexceed said predetermined value, said 13. An excitation system for a dynamo-electric I machine of a power system including a iield exi citing winding, an auxiliary dynamo-electric ma-A chine arranged to energize saidyeld exciting winding, means including a second 'eldexciting winding for said auxiliary dynamo-electricmachine for varying the energization provided -bysaid auxiliary dynamo-electric machine to of current and voltage variations below a predetermined value of electric current, a third iield exciting winding for said auxiliary dynamoi electric machine, means for varying the energization provided by said aumliary dynamo-electric machine to limit the current ot said firstmentioned dynamo-electric machine to a prede- 1 termined mammum value, andmeans for varyingthe energization of said third eld exciting winding for limiting the energization of said rst-mentioned iield exciting winding substantially to a predetermined maximum value.

14. An excitation system for a dynamo-electric machine of a power system including a neld exciting winding, an auxiliary dynamo-electric machine arranged to energize said iield exciting winding, means including a second eld exciting winding for said auxiliary dynamo-electric machine for varying the energizationprovided by said auxiliary dynamo-electric machine to last-mentioned means also being adapted to limit automatically the energization of said rstmentioned iield exciting winding substantially to a predetermined mammum value.

16. An excitation system for a dynamo-electric machine .or a power system including a held exciting winding, an auxiliary dynamo-electric machine arranged to energize said iield exciting winding, means including a second eld excitin g winding for said auxiliary dynamo-electric machine for varying the energization provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said firstcluding said third iield exciting winding for limiting theenergization of said mst-mentioned ileld exciting winding substantially to a predetermined maximum value.

17. An excitation system for a dynamo-electric machine of a power system including a eld exciting winding, an auxiliary dynamo-electric machine arranged to energize said eld exciting winding, means including a second eld exciting winding for said auxiliary dynamo-electric ma- A chine arranged to be energized substantially reherently the power output of said first-mentioned dynamo-electric machine to a value such that said power output together with the losses of said power system and said machine is a substantially constant value within a given range oi current and voltage variations below a predetermined value of electric load current thereof, and means for varying the energization provided by said, auxiliary dynamo-electric machine to limit the current of said iirst-mentioned dynamo-electric machine to a predetermined maximum value.

18. An excitation system for a dynamo-electric machine of a power system including a field exciting winding. an auxiliary dynamo-electric machine arranged to yenergize said ield exciting winding, means including a second field exciting winding for said auxiliarydynamo-electric machine arranged to be energized substantially responsive to the power of said power system for varying the energization provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said first-mentioned dynamo-electric machine to a value such that said power outputI together with the losses of said power system and said machine is a substantially constant value within a given range of current and voltage variations below a predetermined value of electric load current thereof, means for varying the energization provided by said auxiliary dynamo-electric machine to limit the current of said mst-mentioned dynamoelectric machine to a predetermined maximum value, and means responsive to the energization of said mst-mentioned iield exciting winding for varying the energization of said second eld exciting winding for limiting the energization cf said mst-mentioned ileld exciting winding substantially to a predetermined maximum value.

19. An excitation system for a dynamo-electric machine of a power system including a'iield exciting winding, an auxiliary dynamo-electric machine arranged to energize said field exciting winding, means including a second field exciting winding for said auxiliary dynamo-electric machine for varying the energizatio'n, provided by said auxiliary dynamo-electric machine to regulate inherently the power output of said firstmentioned dynamo-electric machine to a value such that said output together with the losses of said power system and said machine is a substantially constant value within a 'given range of current and voltage variations below a predetermined value of electric current, means dependent on the load current of said ilrst-mentioned dynamo-electric machine for varying the energization provided by said auxiliary dynamo-electric machine to limit the current of said first-mentioned dynamo-electric machine to a predetermined maximum value, and means dependent on the energization of said first-mentioned ileld exciting winding for varying the energization oi' said second field exciting winding for limiting the energizaticn of said first-mentioned eld exciting winding substantially to a predetermined maximum value.

MARTIN A. EDWARDS. 

